The need to accurately and precisely measure the flow of current in electronic systems is becoming increasingly critical and widespread. The growth of battery-powered portable devices has increased the need to minimize energy usage and manage power requirements of devices, and the spread of electrically actuated systems in various practical applications account for the widespread need.
The latest trends in power management products require performing not only power rationing for downstream devices, but also removal detection events, detecting when a device is physically removed from a circuit. Power rationing requires measuring large amounts of current data of the order of amperes, but removal detection events require measuring low current, usually of the order of few hundred micro amperes. At the end of the charging cycle, for example, a battery under charge may draw extremely low current, but the system needs to know when the device is actually removed from the charger.
A conventional solution for removal detection is to employ a very high resolution analog-to-digital converter (ADC) to measure current over a wide range, from Amperes on the high-end to micro amperes at the lower end of the scale. The high resolution ADCs require output of 16-bits and more. As is well understood in the art, that degree of resolution calls for high die area requirements. Moreover, adding high resolution ADCs to an integrated chip increases the overall power consumption of the chip.
Alternatively, designers use multiple ADCs to perform the desired current sensing and measurement. That solution, however, increases the die area requirements. In addition, multiple ADCs increase the digital signal processing requirements as well as the power consumption.
Thus, there remains a need for an ADC capable of accurately measuring high resolution current values for efficient power management.